1. Field of the Invention
The present invention relates to a photoelectric touch panel and more particularly to a photoelectric touch panel comprising arrays of light emitting elements and photosensitive elements arranged in a frame configuration on the circumference of a CRT display screen in which a matrix of infrared beams is formed and it is adapted such that, when an object is put in the matrix of infrared beams, the shielded beams thereby cause the coordinates of the shielded position to be input to a computer.
2. Description of the Prior Art
As a photoelectric touch panel of the described type such one as shown in FIG. 3 is known. Referring to FIGS. 3, 1a, 1b, 1c, and 1d are arrays disposed in a frame configuration in front of a screen of a CRT display, in which the arrays 1a and 1b, which are not facing each other, are that of light emitting elements. Namely, LEDs 2, 2, . . . are arranged there at regular intervals. On the other hand, the arrays 1c and 1d, which face the arrays 1a and 1b, are of photosensitive elements. That is, phototransistors 3, 3, . . . are arranged there at regular intervals corresponding to the LEDs 2, 2, . . . . Infrared beams 4, 4, . . . from the LEDs 2, 2, . . . are arranged in a matrix in front of the screen. If any position on the screen is touched by such an object as a finger or a touch pen, specific infrared beams 4, 4 are shielded thereby and causes the X and Y coordinates of the shielded position to be input to a computer.
In such a photoelectric touch panel, as shown in FIG. 2, the phototransistors 3, 3, . . . are put in cylindrical enclosures 5, 5, . . . with their ends sunk to a certain depth from the opening of the enclosure to prevent scattered light from outside, sun beams including infrared rays to a considerable degree in particular, from entering into the phototransistors 3, and the openings of the enclosures 5, 5, . . . are provided with filters 6 which transmit only infrared beams therethrough.
In the arrangement of such enclosures for the phototransistors 3, 3, . . . , however, there was a problem that it was very difficult to construct the enclosure portions 5, 5, . . . in a manner to fit the array of a large number of phototransistors 3, 3, . . . and therefore it was unable to make the constructing work efficiently.